US20130059691A1 - Silent chain - Google Patents
Silent chain Download PDFInfo
- Publication number
- US20130059691A1 US20130059691A1 US13/596,157 US201213596157A US2013059691A1 US 20130059691 A1 US20130059691 A1 US 20130059691A1 US 201213596157 A US201213596157 A US 201213596157A US 2013059691 A1 US2013059691 A1 US 2013059691A1
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- Prior art keywords
- guide
- chain
- plates
- link plates
- link
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- Granted
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- 238000005452 bending Methods 0.000 claims abstract description 15
- 230000005540 biological transmission Effects 0.000 description 14
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 238000003780 insertion Methods 0.000 description 2
- 230000037431 insertion Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002028 premature Effects 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
Images
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16G—BELTS, CABLES, OR ROPES, PREDOMINANTLY USED FOR DRIVING PURPOSES; CHAINS; FITTINGS PREDOMINANTLY USED THEREFOR
- F16G13/00—Chains
- F16G13/02—Driving-chains
- F16G13/04—Toothed chains
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16G—BELTS, CABLES, OR ROPES, PREDOMINANTLY USED FOR DRIVING PURPOSES; CHAINS; FITTINGS PREDOMINANTLY USED THEREFOR
- F16G13/00—Chains
- F16G13/02—Driving-chains
- F16G13/06—Driving-chains with links connected by parallel driving-pins with or without rollers so called open links
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16G—BELTS, CABLES, OR ROPES, PREDOMINANTLY USED FOR DRIVING PURPOSES; CHAINS; FITTINGS PREDOMINANTLY USED THEREFOR
- F16G13/00—Chains
- F16G13/02—Driving-chains
- F16G13/08—Driving-chains with links closely interposed on the joint pins
Definitions
- This invention relates to a silent chain having guide plates and link plates that engage with sprockets.
- the silent chain can be used, for example, to transmit power in automobile engines and industrial machinery.
- a typical silent chain comprises alternating guide rows and non-guide rows, each comprising a set of link plates.
- the link plates of the guide rows and the link plates of the non-guide rows are disposed in interleaved relationship.
- Each guide row is composed of a pair of spaced, opposed, guide plates and a set of intermediate link plates disposed between the guide plates.
- the intermediate link plates are engageable with sprockets of a transmission.
- Each of the non-guide rows is composed of a plurality of inner link plates, which are interleaved with the intermediate link plates of the guide rows and also engageable with the sprockets. Pairs of connecting pins are provided for each pair of guide plates.
- the guide rows and non-guide rows are connected in articulating relationship by the connecting pins.
- a typical silent chain is described in U.S. Pat. No. 6,325,735, granted on Dec. 4, 2001.
- the condition of the chain changes in various ways.
- the chain tends to move laterally, or “swing” in the direction of its width. This movement is sometimes referred to as “lateral swing.”
- a silent chain 501 comprises guide rows 502 , each composed of a pair of guide plates 503 and intermediate link plates 504 , non-guide rows 505 , each composed of a plurality of inner link plates 506 , and pairs of connecting pins 507 fixed to the guide plates 503 .
- the sprocket tooth 509 starts to engage the intermediate link plates 504 and the inner link plates 506 without contacting a guide plate 503 .
- the sprocket tooth 509 contacts the guide plate 503 before it contacts an intermediate or inner link plate, frictional loss and noise are generated due to contact between the guide plate 503 and the sprocket tooth 509 , causing deterioration in the performance of the silent chain.
- the inner link plates 506 can bend the connecting pins 507 , which are held by the pair of guide plates 503 one of which is shown in FIG. 11 . Bending of the connecting pins 507 can occur when the tensile hardness of the guide plate 503 between the pair of connecting pins 507 exceeds the bending rigidity of the connecting pin 507 .
- Bending of the connecting pins 507 causes the guide plates 503 to warp so that they become convex toward the intermediate link plates 504 in the chain width direction. Due to the warp, an inner link plate 506 contacts an inside surface 503 a of the guide plate 503 , causing still more frictional loss when a non-guide row 505 turns relative to an adjacent guide row 502 about the centerline of a connecting pin 507 as the intermediate link plates 504 or the inner link plates 506 start to engage a sprocket.
- the silent chain according to the invention is a chain elongated along a direction of chain travel and comprises alternating guide rows and non-guide rows, each row comprising a set of link plates.
- Each of the guide rows is composed of a pair of guide plates in spaced, opposed relationship, and a plurality of intermediate link plates disposed between the guide plates.
- Each of the non-guide rows is composed of a plurality of inner link plates.
- the intermediate link plates of each guide row are interleaved with inner link plates of two adjacent non-guide rows.
- Two spaced connecting pins are connected to the guide plates of each pair of guide plates, and each of the connecting pins articulably connects a guide row with a non-guide row whereby the guide rows and non-guide rows are disposed in alternating relationship forming a chain.
- the intermediate link plates and the inner link plates are formed with teeth for engagement with the teeth of a sprocket, and the link plates are rotatable about center lines of the connecting pins.
- a characterizing feature of the invention is the fact that the inner profile of each of the guide plates is sufficiently high in relation to a link plate tooth of a link plate that is overlapped by each said guide plate that the engagement between a sprocket tooth and said link plate tooth takes place before engagement of the last mentioned sprocket tooth with said guide plate can take place even when the silent chain moves laterally.
- the tensile hardness of the guide plates is sufficiently low in relation to the bending rigidity of the connecting pins to prevent substantial warping of the guide plates as a result of tension acting on the chain.
- the back surface of each guide plate is configured to avoid contact with a sliding contact surface of a chain guide on which a back surface of a link plate of said chain can slide.
- the tensile hardness of the guide plates is less the bending rigidity of the connecting pins, it is possible to prevent the connecting pins from bending when the chain is under tension, and to prevent the guide plates from warping due to the bending of the connecting pins. Accordingly, it is possible to reduce frictional contact between the guide plates and the adjacent inner link plates, and thereby achieve a still further reduction in frictional loss.
- a further reduction in frictional losses is achieved by configuring the back surface of the guide plates to avoid contact with the sliding contact surface of a chain guide.
- the invention achieves reduction of frictional losses in three ways: by avoiding premature contact between a sprocket tooth and a guide plate, by avoiding warping of the guide plates due to chain tension, and by reducing the contact area between the back of the chain and the sliding contact surface of a chain guide.
- Another aspect of the invention is the formation of the back surfaces of the guide plates so that they have a pair of spaced portions connected by a concave portion.
- the spaced portions have a back surface height greater than the back surface height of the concave portion, and the back surface heights of the spaced portions are lower than the back surface heights of the intermediate link plates between the guide plates and lower than the back surface height of the inner link plates of the non-guide rows.
- the concave configuration of the backs of the guide plates reduces the tensile hardness of the guide plate, making it possible to avoid substantial warping of the guide plates as a result of chain tension. In addition avoiding contact between the back surfaces of the guide plates and the chain guide reduces frictional loss.
- the back surfaces of the link plates have a convex arcuate shape along the direction of travel of the chain.
- At least some of the link plates have back surfaces with convex arcuate shapes in section planes transverse to the direction of travel of the chain. Accordingly, it is possible to achieve a still further reduction in the overall frictional loss of a silent chain transmission.
- At least one link plate in at least one set of the rows from a set consisting of the guide rows of the chain and a set consisting of the non-guide rows of the chain, has a back surface configured to avoid contact with a sliding-contact surface when said sliding contact surface is in sliding contact with backs of other link plates in the same row.
- FIG. 1 is a side elevational view of part of a silent chain transmission incorporating a silent chain in accordance with the invention
- FIG. 2 is a sectional a part of the silent chain shown in FIG. 1 on a plane in which the center lines of the connecting pins;
- FIG. 3A is a side elevational of a part of the silent chain transmission, showing the engagement of a guide row of the silent chain in FIG. 1 with a sprocket;
- FIG. 3B is an enlargement of a part of the transmission of FIG. 3A outlined by a broken line circle in FIG. 3A ;
- FIG. 3C is a sectional view taken on section plane IIIC-IIIC in FIG. 3B ;
- FIG. 4A is a side elevational view of a part of the silent chain transmission, showing the engagement of a non-guide row of the silent chain in FIG. 1 with a sprocket
- FIG. 4B is an enlargement of a part of the transmission of FIG. 4A outlined by a broken line circle in FIG. 4A ;
- FIG. 5 is a side view showing a part of the silent chain of FIG. 1 in sliding contact with a chain guide;
- FIG. 6 is a sectional view taken on section plane VI-VI in FIG. 5 ;
- FIG. 7 is a sectional view corresponding to FIG. 6 but showing a first modification of the invention.
- FIG. 8 is another sectional view corresponding to FIG. 6 but showing another modification of the invention.
- FIG. 9A is a sectional view showing engagement of a guide row of a conventional chain with a sprocket
- FIG. 9B is an enlarged view of a part of the silent chain transmission shown in FIG. 9A outlined by a broken line circle in FIG. 9A ;
- FIG. 10A is a sectional view showing engagement of a non-guide row of a conventional chain with a sprocket
- FIG. 10B is an enlarged view of a part of the silent chain transmission shown in FIG. 10A outlined by a broken line circle in FIG. 10A ;
- FIG. 11 is a sectional view of part of a conventional the silent chain as shown in FIG. 9A , taken on a plane in which the centerline of the connecting pins lie.
- a silent chain 100 is incorporated into a silent chain transmission 1 , which comprises a plurality of sprockets with which the chain is engaged, one such sprocket being shown in FIG. 1 .
- the transmission also includes, a chain guide 5 ( FIG. 5 ) on which the silent chain slides.
- the silent chain 100 is composed of a plurality of guide rows 103 , a plurality of non-guide rows 104 , and a plurality of connecting pins 105 that connect the guide rows 103 with the non-guide rows 104 in alternation relationship to form an endless chain.
- the sprocket mechanism is composed of a plurality of sprockets, i.e., one or more driving sprockets 3 and one or more driven sprocket 2 , each having a plurality of sprocket teeth 4 .
- FIG. 1 shows a driving sprocket 3 that rotates in a direction R about an axis Ls.
- FIGS. 5 and 6 shows a chain guide 6 which can be either a tensioner lever that applies tension to the chain, or a stationary chain guide. In either case, the chain guide has a sliding-contact surface 7 on which the back of the traveling silent chain 100 slides
- the traveling direction is the direction in which the silent chain 100 moves
- the chain width direction (see FIG. 2 ) is a direction parallel to the centerline Lc of the connecting pins about which a non-guide row 104 bends relative to a guide row 103 .
- These centerline Lc are parallel to the axis of rotation Ls of the sprocket 3 .
- the front and back directions are respectively the direction of chain travel and the direction opposite to the direction of chain travel.
- a side view is a view from a direction in parallel with the centerline Lc and the sprocket axis Ls
- the radial direction is a direction perpendicular the axis Ls of the sprocket 3 .
- a lateral swing is condition in which the traveling silent chain 100 swings in the chain width direction, and also includes a condition in which the silent chain 100 is slanted in the chain width direction.
- the silent chain 100 has guide rows 103 , each comprising a pair of guide plates 110 and a number of intermediate link plates 130 .
- the chain also has non-guide rows 104 , each having a number of inner link plates 150 exceeding by one the number of intermediate link plates in a guide row.
- Each guide row comprises a pairs of connecting pins 105 each pin being fixed to both of the opposite guide plates 110 .
- the pins are separated from each other in the direction of chain travel.
- Each pin connect the intermediate link plates 130 of a guide row with the inner link plates 150 of an adjacent non-guide row in interleaved relationship, allowing both sets of link plates to rotate about the center line Lc of the pin.
- gaps between the guide plates 110 , the intermediate link plates 130 and the inner link plates 150 and gaps between the connecting pins 150 and pin insertion holes 131 and 151 are exaggerated.
- a plurality of intermediate link plates 130 is disposed between the pair of guide plates 110 in the chain width direction in each guide row 103 .
- Each guide plate 110 is provided with pin holding holes 111 at positions separated from each other in the direction of chain travel, i.e., in the front-back direction.
- each of the connecting pins 105 are fixed in the holding holes of the guide plates 110 by suitable means such as press-fitting or caulking.
- the inner link plates 150 in each non-guide row 104 are disposed in interleaved relationship with the intermediate link plates and guide plates of each of two adjacent guide rows. As shown in FIG. 2 , inner link plates 150 E, located at ends of each non-guide row 104 are disposed next to guide plates 110 in adjacent guide rows.
- the intermediate link plate 130 and the inner link plate 150 respectively have a pair of link teeth 132 and 133 and 152 and 153 that project radially inward for engagement with sprocket teeth.
- Teeth 132 and 133 are front and rear link teeth respectively, and teeth 152 and 153 are front and rear link teeth respectively.
- the respective link teeth 132 and 133 have inner flanks 144 and 145 and outer flanks 146 and 147 , which can contact sprocket teeth 4 .
- the respective link teeth 152 and 153 likewise have inner flanks 164 and 165 and outer flanks 166 and 167 which can contact sprocket teeth 4 .
- the pairs of the inner flanks 144 and 145 and 164 and 165 of the respective link plates 130 and 150 are front inner flanks ( 144 and 164 ) and rear inner flanks ( 144 and 155 ), and the pairs of the outer flanks 146 and 147 and 166 and 167 are front outer flanks ( 146 and 166 ) and rear outer flanks ( 147 and 167 ).
- the intermediate link plates 130 and the inner link plates 150 are provided respectively with pin insertion holes 131 and 151 through which the connecting pins 105 are inserted as shown in FIG. 2 .
- Each pair of connecting pins 105 held by a pair of guide plates 110 in a guide row 103 connects a link plate group composed of the intermediate link plates 130 and the inner link plates 150 of two adjacent non-guide rows, allowing the non-guide rows to articulate with respect to the guide rows about connecting pin centerline Lc.
- the connecting pins 105 shown in the drawings are round pins, the connecting pins can be rocker pins, each composed of two elements having mutually engaging cylindrical surfaces that roll on each other.
- the profiles of the link plates 130 and 150 comprise inner profile surfaces 142 and 162 on the side where the sprocket teeth 4 are located and outer profile surfaces, i.e., back surfaces, 141 and 161 , located on a side opposite from the inner profile surfaces 142 and 162 .
- the pin reference plane A passing through the center lines Lc of the pins marks the border between the inner and outer profile surfaces.
- the side where the sprocket tooth 4 is located is radially inward of the portion 101 of the chain wrapped onto the sprocket 3 , and the side opposite from the inner profile surfaces is outward in the radial direction.
- the inner profile surfaces 142 and 162 have flanks 144 through 147 ( FIG. 3A) and 164 through 167 ( FIG. 4A ).
- the back surfaces 141 and 161 of the respective link plates 130 and 150 are convex, having arc-shaped intermediate parts 141 a and 161 a, where the back surface heights H 4 and H 6 are maximum.
- the back surface heights H 4 and H 6 of the link plates and the back surface height H 2 of the guide plates are distances respectively from the pin reference plane A to the back surfaces of the plates.
- the respective back surfaces 141 and 161 that slide on surface 7 of the guide are convex, arc-shaped, surfaces in a section plane orthogonal to the pin reference plane A.
- the “arc-shaped” surfaces 121 and 141 can be in the form of an arc having a single radius of curvature, a curve composed of a plurality of arcs having different radii of curvature that merge together smoothly, or an approximated arc.
- the silent chain 100 is a referred to as an inner flank-engaging, outer flank-seating type chain.
- the ordinary position of the chain is a position in which the sprocket tooth 4 is located within the span W ( FIG. 2 ) between the guide plates 110 of guide row 103 .
- neither of the guide plates 110 overlaps the sprocket tooth in the chain width direction.
- a sprocket tooth may not be within the span W between the guide plates 110 .
- the respective guide plates 110 have an outer side surface 112 and an inner side surface 113 .
- the guide plate 110 has an inner profile surface 122 on the side where the sprocket tooth 4 is located and an outer profile surface, i.e., a back surfaces 121 , located on the side opposite from the inner profile surface 122 .
- the portion 115 which has a maximum dimension in the direction of chain travel, constitutes the border between the inner and outer profile surfaces of the guide plate.
- the inner profile surface 122 of the guide plate 110 has an inner end surface 123 having a portion located innermost in the radial direction, and a pair of inner side end surfaces 124 and 125 each extending from the inner end surface 123 to a maximum width portion 115 .
- the inner end surface 123 When seen from the side, the inner end surface 123 intersects the inner flanks 144 and 145 of an intermediate link plate 130 at locations near the ends of surface 123 , and the inner end surface 123 is located radially inward in the radial direction of inner side end surfaces 124 and 125 .
- the straight inner side end surfaces 124 and 125 are front and rear inner side end surfaces respectively.
- the inner end surface 123 is connected to front inner side end surface 124 by an arc-shaped connecting part.
- the rear inner side end surface 125 is similarly connected to the inner end surface 123 by an arc-shaped connecting part.
- the respective inner side end surfaces 124 and 125 can otherwise be straight.
- This shape of the guide plate 110 makes it possible to form the guide plate easily and to enhance its bending rigidity in the chain width direction even when the back surface 121 is concave.
- the guide plate can be made more rigid and resistant to bending than a guide plate in which the inner profile surface has one or more concave portions. Consequently it is possible to prevent the guide plate 110 from warping due to chain tension acting on the guide plate through a connecting pin as in the case of guide plate 503 in FIG. 11 .
- the back surface 121 of the guide plate 110 has an arc-shaped concave portion 121 c formed so that the back surface has two parts 121 a and 121 b where the back surface height H 2 is maximum.
- the arc-shape concave portion 121 c has a maximum depth at 121 e where the back surface height H 2 is minimum. The maximum depth is at a location midway between the locations of the connecting pins 105 .
- the concave portion 121 c is located radially inward relative to parts 121 a and 121 b.
- the tensile hardness of the guide plate 110 having the concave portion 121 c formed as described above is lower than that of a guide plate having no concave portion, and selected so that it is to be smaller than the bending rigidity of the connecting pin 105 . Therefore, due to the ductility of the guide plates and the rigidity of the connecting pins, a force exerted by the link plates on the connecting pins due to excessive chain tension tends to stretch the guide plates instead of bend the connecting pins. Consequently, warping of the guide plates as depicted in FIG. 11 can be suppressed, and frictional loss caused by contact of the inner side surface 113 of the guide plates with the endmost inner link plates of the guide rows can be avoided or at least significantly reduced.
- the back surface height H 2 of the back surface 121 is less than the back surface heights H 4 and H 6 of the back surfaces 141 and 161 of the respective link plates 130 and 150 within the range where the back surface 121 of the guide plate 110 overlaps the link plates 130 and 150 in the direction of chain travel.
- the guide plate 110 is prevented from contacting the sliding-contact surface 7 of the guide even when the back surfaces 141 and 161 of the respective link plates 130 and 150 are in sliding contact with guide surface 7 while the chain is in a slanted contact condition. Accordingly a further reduction in frictional loss can be achieved.
- engagement starting points P 3 and P 5 of the respective front inner flanks 144 and 164 of the intermediate and inner link plates 130 and 150 with the sprocket tooth 4 are at positions such that the guide plate 110 is prevented from contacting the sprocket tooth 4 before the front inner flanks 144 and 164 of the respective link plates 130 and 150 start to engage the sprocket tooth 4 . Therefore, contact takes place in the same manner as when the silent chain 100 is located at its ordinary position.
- the guide plate 110 is configured so that, even when the chain is in a laterally swinging condition, neither the inner end surface 123 nor either of the inner side end surfaces 124 and 125 can engage the sprocket tooth 4 a before the front inner flank surface 144 of the intermediate link plate 130 starts to engage the sprocket tooth 4 a.
- the entire guide plate 122 is located radially outward from the engagement starting point P 3 before the front inner flank surface 144 starts to engage the sprocket 3 .
- the inner end surface 123 is configured so that the sprocket tooth 4 is located within the span W ( FIG. 5 ) in the overlapping portion 117 in order to avoid contact between the inner end surface 123 and the sprocket tooth 4 a before the front inner flank surface 144 starts to engage the sprocket tooth 4 a.
- the guide plate 110 can be configured so that no part of the guide plate overlaps the sprocket tooth 4 when seen from the side before the intermediate link plate 130 starts to engage with the sprocket tooth 4 .
- the guide plate 110 is configured to prevent the inner end surface 123 and the both inner side end surfaces 124 and 125 from contacting the sprocket tooth 4 before the front inner flank surface 164 of the inner link plate 150 starts to engage the sprocket tooth 4 when the chain is in the lateral swinging condition.
- the entire inner profile surface 122 including the rear inner side end surface 125 , is located radially outwardly from the engagement starting point P 5 before the front inner flank surface 144 starts to engage the sprocket tooth 4 , and the no part of the guide plate 110 overlaps the sprocket tooth 4 .
- the guide plate 110 is configured to avoid contact between the inner profile surface 122 of the guide plate 110 and the sprocket tooth 4 b, or so that the guide plate 110 does not overlap the sprocket tooth 4 when seen from the side, throughout the interval from the start of the engagement of the front inner flank surface 144 of the inner link plate 150 with the sprocket tooth 4 until the both outer flanks 146 and 147 of the intermediate link plate 130 located ahead of the inner link plate 150 seat on the sprocket 3 by contact respectively with sprocket tooth 4 c ahead of the sprocket tooth 4 a and sprocket tooth 4 b.
- the rear inner side end surface 125 of the guide plate is configured so that it is prevented from contacting the sprocket tooth 4 or so that the rear inner side end surface 125 does not overlap the sprocket tooth 4 when seen from the side, throughout the interval from the start of engagement of the inner link plate 150 with the sprocket tooth 4 until the intermediate link plate 130 located ahead of the inner link plate 150 seats on the sprocket 3 .
- the guide plate 110 is configured to prevent the rear inner side end surface 125 of the guide plate 110 from contacting the sprocket tooth 4 from the start of engagement of the inner link plate 150 with the sprocket until the intermediate link plate 130 seats on the sprocket, it is possible to downsize the guide plate 110 still further by reducing its radial dimensions.
- the tensile hardness of the guide plate 110 is smaller than the bending rigidity of the connecting pins 105 it is possible to suppress warping of the guide plates due to bending of the connecting pins. Suppression of bending of the guide plates, in turn reduces the frictional loss caused by excessive frictional contact between the guide plates and adjacent outermost intermediate link plates.
- a further reduction of frictional loss is realized by configuring the back surfaces 121 of the guide plates so that they are prevented from contacting the sliding contact surface of a chain guide on which the backs of the intermediate and inner link plates slide.
- the concave configuration of the back surface of the guide plate 110 also reduces the tensile hardness of the guide plate, reducing the tendency of the connecting pins to bend and cause warping of the guide plate as a result of tension on the chain
- the convex, arc-shaped configurations of the backs 141 and 161 of the respective link plates reduce the contact area between the chain and the sliding-contact surface of the chain guide, further reducing frictional loss.
- the convex, arc-shaped, configurations of the backs 141 and 161 while advantageous, are of course optional. Many advantages of the invention can be realized in a chain the link plates of which do not have convex backs.
- an inner link plate 150 can be a sliding-contact link plate the back surface 161 of which has an arcuate shape in the direction of chain travel and an arc-shaped transverse section in the direction of the width of the chain.
- the intermediate link plates 130 in the guide rows, and, optionally, some of the other inner link plates 150 in the non-guide rows, can be configured to avoid contact with the sliding contact surface of a guide.
- an intermediate link plate 130 of the guide rows can a sliding-contact link plate the back surface 141 of which has an arcuate shape in the direction of chain travel and an arc-shaped transverse section in the direction of the width of the chain.
- the inner link plates 150 , and optionally one or more of the other intermediate link plates 130 can be configured to avoid the contact with the sliding contact surface of a guide.
- the silent chain may be of a type other than the inner-flank-engaging and outer-flank-seating type chain, such as an outer-flank-engaging and outer-flank-seating type chain or an inner-flank-engaging and inner-flank-seating type chain.
- Advantages of the invention can be realized both in an endless silent chain, or in a reciprocating silent chain not formed into an endless loop.
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Abstract
Description
- This application claims priority on the basis of Japanese Patent Application No. 2011-193205, filed on Sep. 5, 2011. The disclosure of Japanese Patent Application No. 2011-193205 is incorporated by reference.
- This invention relates to a silent chain having guide plates and link plates that engage with sprockets. The silent chain can be used, for example, to transmit power in automobile engines and industrial machinery.
- A typical silent chain comprises alternating guide rows and non-guide rows, each comprising a set of link plates. The link plates of the guide rows and the link plates of the non-guide rows are disposed in interleaved relationship.
- Each guide row is composed of a pair of spaced, opposed, guide plates and a set of intermediate link plates disposed between the guide plates. The intermediate link plates are engageable with sprockets of a transmission. Each of the non-guide rows is composed of a plurality of inner link plates, which are interleaved with the intermediate link plates of the guide rows and also engageable with the sprockets. Pairs of connecting pins are provided for each pair of guide plates. In the silent chain, the guide rows and non-guide rows are connected in articulating relationship by the connecting pins. A typical silent chain is described in U.S. Pat. No. 6,325,735, granted on Dec. 4, 2001.
- In the operation of a silent chain transmission, the condition of the chain changes in various ways. In particular, the chain tends to move laterally, or “swing” in the direction of its width. This movement is sometimes referred to as “lateral swing.”
- As shown in
FIGS. 9A and 9B , asilent chain 501 comprisesguide rows 502, each composed of a pair ofguide plates 503 andintermediate link plates 504,non-guide rows 505, each composed of a plurality ofinner link plates 506, and pairs of connectingpins 507 fixed to theguide plates 503. - When lateral swing occurs, if an
inner end face 503 a of aguide plate 503 is located in the vicinity of anengagement starting point 504 p, at which aninner flank 504 a of anintermediate link plate 504 starts to engage asprocket tooth 509, it is possible for theguide plate 503 to contact thesprocket tooth 509 before theintermediate link plate 504 contacts the sprocket tooth. Furthermore, as shown inFIGS. 10A and 10B , when anon-guide row 505 starts to engage the drivingsprocket 508, lateral swing can result in contact between anend surface 503 b of theguide plate 503 and asprocket tooth 509 before theinner link plate 506 contacts the sprocket tooth. - Ordinarily, the
sprocket tooth 509 starts to engage theintermediate link plates 504 and theinner link plates 506 without contacting aguide plate 503. However, if thesprocket tooth 509 contacts theguide plate 503 before it contacts an intermediate or inner link plate, frictional loss and noise are generated due to contact between theguide plate 503 and thesprocket tooth 509, causing deterioration in the performance of the silent chain. - Furthermore, as shown in
FIG. 11 , when tension in thesilent chain 501 increases, theinner link plates 506 can bend the connectingpins 507, which are held by the pair ofguide plates 503 one of which is shown inFIG. 11 . Bending of the connectingpins 507 can occur when the tensile hardness of theguide plate 503 between the pair of connectingpins 507 exceeds the bending rigidity of the connectingpin 507. - Bending of the connecting
pins 507 causes theguide plates 503 to warp so that they become convex toward theintermediate link plates 504 in the chain width direction. Due to the warp, aninner link plate 506 contacts aninside surface 503 a of theguide plate 503, causing still more frictional loss when anon-guide row 505 turns relative to anadjacent guide row 502 about the centerline of a connectingpin 507 as theintermediate link plates 504 or theinner link plates 506 start to engage a sprocket. - As shown in
FIGS. 9A and 9B , if theback surfaces guide plate 503, theintermediate link plate 504 and theinner link plate 506 are co-planar, the contact area of the back of the chain with the sliding-contact surface of a chain guide (not shown) increases, resulting in an additional frictional loss. - The several frictional losses described above reduce the power-transmitting efficiency
silent chain 501. Accordingly, there is a need for a silent chain having a plate configuration that reduces frictional losses and improves power transmitting efficiency and noise performance. - The silent chain according to the invention is a chain elongated along a direction of chain travel and comprises alternating guide rows and non-guide rows, each row comprising a set of link plates. Each of the guide rows is composed of a pair of guide plates in spaced, opposed relationship, and a plurality of intermediate link plates disposed between the guide plates. Each of the non-guide rows is composed of a plurality of inner link plates. The intermediate link plates of each guide row are interleaved with inner link plates of two adjacent non-guide rows. Two spaced connecting pins are connected to the guide plates of each pair of guide plates, and each of the connecting pins articulably connects a guide row with a non-guide row whereby the guide rows and non-guide rows are disposed in alternating relationship forming a chain.
- The intermediate link plates and the inner link plates are formed with teeth for engagement with the teeth of a sprocket, and the link plates are rotatable about center lines of the connecting pins.
- A characterizing feature of the invention is the fact that the inner profile of each of the guide plates is sufficiently high in relation to a link plate tooth of a link plate that is overlapped by each said guide plate that the engagement between a sprocket tooth and said link plate tooth takes place before engagement of the last mentioned sprocket tooth with said guide plate can take place even when the silent chain moves laterally. In addition, the tensile hardness of the guide plates is sufficiently low in relation to the bending rigidity of the connecting pins to prevent substantial warping of the guide plates as a result of tension acting on the chain. Moreover the back surface of each guide plate is configured to avoid contact with a sliding contact surface of a chain guide on which a back surface of a link plate of said chain can slide.
- With this arrangement, even when the silent chain is moved laterally relative to the sprockets, because the engagement starting point of one link plate of the silent chain is at a position where the guide plate does not contact the sprocket tooth before an adjacent link plate starts to engage the sprocket tooth, it is possible to prevent the guide plate from contacting the sprocket teeth until the sprocket teeth start to engage the inner flanks of the link plates. Accordingly, it is possible to achieve the same engagement starting performance when the chain is moved laterally as when the chain is in its normal position. Frictional losses and noise which would otherwise be caused by contact between the guide plate and a sprocket tooth can be avoided and improved power transmitting efficiency can be achieved.
- In addition, because the tensile hardness of the guide plates is less the bending rigidity of the connecting pins, it is possible to prevent the connecting pins from bending when the chain is under tension, and to prevent the guide plates from warping due to the bending of the connecting pins. Accordingly, it is possible to reduce frictional contact between the guide plates and the adjacent inner link plates, and thereby achieve a still further reduction in frictional loss.
- A further reduction in frictional losses is achieved by configuring the back surface of the guide plates to avoid contact with the sliding contact surface of a chain guide.
- Thus the invention achieves reduction of frictional losses in three ways: by avoiding premature contact between a sprocket tooth and a guide plate, by avoiding warping of the guide plates due to chain tension, and by reducing the contact area between the back of the chain and the sliding contact surface of a chain guide.
- Another aspect of the invention is the formation of the back surfaces of the guide plates so that they have a pair of spaced portions connected by a concave portion. The spaced portions have a back surface height greater than the back surface height of the concave portion, and the back surface heights of the spaced portions are lower than the back surface heights of the intermediate link plates between the guide plates and lower than the back surface height of the inner link plates of the non-guide rows.
- The concave configuration of the backs of the guide plates reduces the tensile hardness of the guide plate, making it possible to avoid substantial warping of the guide plates as a result of chain tension. In addition avoiding contact between the back surfaces of the guide plates and the chain guide reduces frictional loss.
- According to still another aspect of the invention, the back surfaces of the link plates have a convex arcuate shape along the direction of travel of the chain. With this arrangement, it becomes possible to reduce the contact area of the back surfaces with the sliding contact surface of a chain guide and thereby achieve a still greater reduction in the overall frictional loss in the operation of a silent chain transmission.
- In still another aspect of the invention, at least some of the link plates have back surfaces with convex arcuate shapes in section planes transverse to the direction of travel of the chain. Accordingly, it is possible to achieve a still further reduction in the overall frictional loss of a silent chain transmission.
- In another aspect of the invention, in at least one set of the rows from a set consisting of the guide rows of the chain and a set consisting of the non-guide rows of the chain, at least one link plate has a back surface configured to avoid contact with a sliding-contact surface when said sliding contact surface is in sliding contact with backs of other link plates in the same row.
- With this arrangement, it is possible to reduce still further the contact area between the chain and the sliding contact surface of a guide, and thereby achieve a still greater reduction in the overall frictional loss in the operation of a silent chain transmission.
-
FIG. 1 is a side elevational view of part of a silent chain transmission incorporating a silent chain in accordance with the invention; -
FIG. 2 is a sectional a part of the silent chain shown inFIG. 1 on a plane in which the center lines of the connecting pins; -
FIG. 3A is a side elevational of a part of the silent chain transmission, showing the engagement of a guide row of the silent chain inFIG. 1 with a sprocket; -
FIG. 3B is an enlargement of a part of the transmission ofFIG. 3A outlined by a broken line circle inFIG. 3A ; -
FIG. 3C is a sectional view taken on section plane IIIC-IIIC inFIG. 3B ; -
FIG. 4A is a side elevational view of a part of the silent chain transmission, showing the engagement of a non-guide row of the silent chain inFIG. 1 with a sprocket -
FIG. 4B is an enlargement of a part of the transmission ofFIG. 4A outlined by a broken line circle inFIG. 4A ; -
FIG. 5 is a side view showing a part of the silent chain ofFIG. 1 in sliding contact with a chain guide; -
FIG. 6 is a sectional view taken on section plane VI-VI inFIG. 5 ; -
FIG. 7 is a sectional view corresponding toFIG. 6 but showing a first modification of the invention; -
FIG. 8 is another sectional view corresponding toFIG. 6 but showing another modification of the invention; -
FIG. 9A is a sectional view showing engagement of a guide row of a conventional chain with a sprocket; -
FIG. 9B is an enlarged view of a part of the silent chain transmission shown inFIG. 9A outlined by a broken line circle inFIG. 9A ; -
FIG. 10A is a sectional view showing engagement of a non-guide row of a conventional chain with a sprocket; -
FIG. 10B is an enlarged view of a part of the silent chain transmission shown inFIG. 10A outlined by a broken line circle inFIG. 10A ; and -
FIG. 11 is a sectional view of part of a conventional the silent chain as shown inFIG. 9A , taken on a plane in which the centerline of the connecting pins lie. - As shown in
FIGS. 1 and 2 , asilent chain 100 is incorporated into asilent chain transmission 1, which comprises a plurality of sprockets with which the chain is engaged, one such sprocket being shown inFIG. 1 . The transmission also includes, a chain guide 5 (FIG. 5 ) on which the silent chain slides. - The
silent chain 100 is composed of a plurality ofguide rows 103, a plurality ofnon-guide rows 104, and a plurality of connectingpins 105 that connect theguide rows 103 with thenon-guide rows 104 in alternation relationship to form an endless chain. - The sprocket mechanism is composed of a plurality of sprockets, i.e., one or
more driving sprockets 3 and one or more drivensprocket 2, each having a plurality ofsprocket teeth 4. -
FIG. 1 shows a drivingsprocket 3 that rotates in a direction R about an axis Ls. -
FIGS. 5 and 6 shows achain guide 6 which can be either a tensioner lever that applies tension to the chain, or a stationary chain guide. In either case, the chain guide has a sliding-contact surface 7 on which the back of the travelingsilent chain 100 slides - As shown in
FIGS. 1 and 2 , the traveling direction is the direction in which thesilent chain 100 moves, and the chain width direction (seeFIG. 2 ) is a direction parallel to the centerline Lc of the connecting pins about which anon-guide row 104 bends relative to aguide row 103. These centerline Lc are parallel to the axis of rotation Ls of thesprocket 3. The front and back directions are respectively the direction of chain travel and the direction opposite to the direction of chain travel. A side view is a view from a direction in parallel with the centerline Lc and the sprocket axis Ls, and the radial direction is a direction perpendicular the axis Ls of thesprocket 3. - A lateral swing is condition in which the traveling
silent chain 100 swings in the chain width direction, and also includes a condition in which thesilent chain 100 is slanted in the chain width direction. - The
silent chain 100 hasguide rows 103, each comprising a pair ofguide plates 110 and a number ofintermediate link plates 130. The chain also hasnon-guide rows 104, each having a number ofinner link plates 150 exceeding by one the number of intermediate link plates in a guide row. Each guide row comprises a pairs of connectingpins 105 each pin being fixed to both of theopposite guide plates 110. The pins are separated from each other in the direction of chain travel. Each pin connect theintermediate link plates 130 of a guide row with theinner link plates 150 of an adjacent non-guide row in interleaved relationship, allowing both sets of link plates to rotate about the center line Lc of the pin. - In
FIGS. 2 and 6 , gaps between theguide plates 110, theintermediate link plates 130 and theinner link plates 150 and gaps between the connectingpins 150 and pin insertion holes 131 and 151 are exaggerated. - A plurality of
intermediate link plates 130 is disposed between the pair ofguide plates 110 in the chain width direction in eachguide row 103. Eachguide plate 110 is provided withpin holding holes 111 at positions separated from each other in the direction of chain travel, i.e., in the front-back direction. - The ends of each of the connecting
pins 105 are fixed in the holding holes of theguide plates 110 by suitable means such as press-fitting or caulking. - The
inner link plates 150 in eachnon-guide row 104 are disposed in interleaved relationship with the intermediate link plates and guide plates of each of two adjacent guide rows. As shown inFIG. 2 ,inner link plates 150E, located at ends of eachnon-guide row 104 are disposed next to guideplates 110 in adjacent guide rows. - As shown in
FIGS. 3A , 3B, 4A and 4B, theintermediate link plate 130 and theinner link plate 150 respectively have a pair oflink teeth Teeth teeth - The
respective link teeth inner flanks outer flanks sprocket teeth 4. Therespective link teeth inner flanks outer flanks sprocket teeth 4. - The pairs of the
inner flanks respective link plates outer flanks - The
intermediate link plates 130 and theinner link plates 150 are provided respectively with pin insertion holes 131 and 151 through which the connectingpins 105 are inserted as shown inFIG. 2 . - Each pair of connecting
pins 105 held by a pair ofguide plates 110 in aguide row 103 connects a link plate group composed of theintermediate link plates 130 and theinner link plates 150 of two adjacent non-guide rows, allowing the non-guide rows to articulate with respect to the guide rows about connecting pin centerline Lc. Although the connectingpins 105 shown in the drawings are round pins, the connecting pins can be rocker pins, each composed of two elements having mutually engaging cylindrical surfaces that roll on each other. - As shown in
FIGS. 3A through 5 , the profiles of thelink plates sprocket teeth 4 are located and outer profile surfaces, i.e., back surfaces, 141 and 161, located on a side opposite from the inner profile surfaces 142 and 162. The pin reference plane A passing through the center lines Lc of the pins marks the border between the inner and outer profile surfaces. The side where thesprocket tooth 4 is located is radially inward of theportion 101 of the chain wrapped onto thesprocket 3, and the side opposite from the inner profile surfaces is outward in the radial direction. The inner profile surfaces 142 and 162 haveflanks 144 through 147 (FIG. 3A) and 164 through 167 (FIG. 4A ). - With reference to
FIGS. 3A and 5 , and as shown inFIG. 5 in particular, the back surfaces 141 and 161 of therespective link plates intermediate parts - The back surface heights H4 and H6 of the link plates and the back surface height H2 of the guide plates are distances respectively from the pin reference plane A to the back surfaces of the plates. As shown in
FIG. 6 , the respective back surfaces 141 and 161 that slide onsurface 7 of the guide are convex, arc-shaped, surfaces in a section plane orthogonal to the pin reference plane A. The “arc-shaped” surfaces 121 and 141 can be in the form of an arc having a single radius of curvature, a curve composed of a plurality of arcs having different radii of curvature that merge together smoothly, or an approximated arc. - As shown in
FIGS. 3A , 3B, 4A and 4B, when thesilent chain 100 travels normally, and theguide row 103 and thenon-guide row 104 engage thesprocket teeth 4, the frontinner flanks respective link plates sprocket tooth 4. The engagement point moves inwardly along thesprocket tooth 4 as the engagement advances, and the engagement points in therespective link plates inner flanks outer flanks outer flanks intermediate link plates 130 of the guide row contact asprocket tooth 4 and bothouter flanks silent chain 100 is a referred to as an inner flank-engaging, outer flank-seating type chain. - The ordinary position of the chain is a position in which the
sprocket tooth 4 is located within the span W (FIG. 2 ) between theguide plates 110 ofguide row 103. Thus neither of theguide plates 110 overlaps the sprocket tooth in the chain width direction. However, when thesilent chain 100 swings laterally, a sprocket tooth may not be within the span W between theguide plates 110. - As shown in
FIG. 2 , therespective guide plates 110 have anouter side surface 112 and aninner side surface 113. As shown inFIGS. 3A and 4A , theguide plate 110 has aninner profile surface 122 on the side where thesprocket tooth 4 is located and an outer profile surface, i.e., a back surfaces 121, located on the side opposite from theinner profile surface 122. Theportion 115 which has a maximum dimension in the direction of chain travel, constitutes the border between the inner and outer profile surfaces of the guide plate. - The
inner profile surface 122 of theguide plate 110 has aninner end surface 123 having a portion located innermost in the radial direction, and a pair of inner side end surfaces 124 and 125 each extending from theinner end surface 123 to amaximum width portion 115. - When seen from the side, the
inner end surface 123 intersects theinner flanks intermediate link plate 130 at locations near the ends ofsurface 123, and theinner end surface 123 is located radially inward in the radial direction of inner side end surfaces 124 and 125. The straight inner side end surfaces 124 and 125 are front and rear inner side end surfaces respectively. - As shown in
FIG. 3B , theinner end surface 123 is connected to front innerside end surface 124 by an arc-shaped connecting part. the rear innerside end surface 125 is similarly connected to theinner end surface 123 by an arc-shaped connecting part. The respective inner side end surfaces 124 and 125 can otherwise be straight. This shape of theguide plate 110 makes it possible to form the guide plate easily and to enhance its bending rigidity in the chain width direction even when theback surface 121 is concave. Thus the guide plate can be made more rigid and resistant to bending than a guide plate in which the inner profile surface has one or more concave portions. Consequently it is possible to prevent theguide plate 110 from warping due to chain tension acting on the guide plate through a connecting pin as in the case ofguide plate 503 inFIG. 11 . - As shown in
FIGS. 5 and 6 , theback surface 121 of theguide plate 110 has an arc-shapedconcave portion 121 c formed so that the back surface has twoparts parts concave portion 121 c has a maximum depth at 121 e where the back surface height H2 is minimum. The maximum depth is at a location midway between the locations of the connecting pins 105. Theconcave portion 121 c is located radially inward relative toparts - The tensile hardness of the
guide plate 110 having theconcave portion 121 c formed as described above is lower than that of a guide plate having no concave portion, and selected so that it is to be smaller than the bending rigidity of the connectingpin 105. Therefore, due to the ductility of the guide plates and the rigidity of the connecting pins, a force exerted by the link plates on the connecting pins due to excessive chain tension tends to stretch the guide plates instead of bend the connecting pins. Consequently, warping of the guide plates as depicted inFIG. 11 can be suppressed, and frictional loss caused by contact of theinner side surface 113 of the guide plates with the endmost inner link plates of the guide rows can be avoided or at least significantly reduced. - As shown in
FIG. 5 , the back surface height H2 of theback surface 121, including that ofportions back surfaces respective link plates back surface 121 of theguide plate 110 overlaps thelink plates - Because of its limited back surface height H2, the
guide plate 110 is prevented from contacting the sliding-contact surface 7 of the guide even when theback surfaces respective link plates guide surface 7 while the chain is in a slanted contact condition. Accordingly a further reduction in frictional loss can be achieved. - When the
silent chain 100 is driven by thesprocket 3 while in a lateral swinging condition, engagement starting points P3 and P5 of the respective frontinner flanks inner link plates sprocket tooth 4, are at positions such that theguide plate 110 is prevented from contacting thesprocket tooth 4 before the frontinner flanks respective link plates sprocket tooth 4. Therefore, contact takes place in the same manner as when thesilent chain 100 is located at its ordinary position. - Therefore, when the intermediate and
inner link plates sprocket tooth 4, the intermediate andinner link plates sprocket tooth 4 before the sprocket tooth can contact theguide plate 110. - Specifically, as shown in
FIG. 3B , theguide plate 110 is configured so that, even when the chain is in a laterally swinging condition, neither theinner end surface 123 nor either of the inner side end surfaces 124 and 125 can engage thesprocket tooth 4 a before the frontinner flank surface 144 of theintermediate link plate 130 starts to engage thesprocket tooth 4 a. - Therefore, the
entire guide plate 122, including theinner end surface 123, is located radially outward from the engagement starting point P3 before the frontinner flank surface 144 starts to engage thesprocket 3. - As shown in
FIGS. 3B and 3C , when theguide plate 110 has an overlappingportion 117 that overlaps thesprocket tooth 4 when seen from the side, theinner end surface 123 is configured so that thesprocket tooth 4 is located within the span W (FIG. 5 ) in the overlappingportion 117 in order to avoid contact between theinner end surface 123 and thesprocket tooth 4 a before the frontinner flank surface 144 starts to engage thesprocket tooth 4 a. - In another example, the
guide plate 110 can be configured so that no part of the guide plate overlaps thesprocket tooth 4 when seen from the side before theintermediate link plate 130 starts to engage with thesprocket tooth 4. - As shown in
FIGS. 4A and 4B , theguide plate 110 is configured to prevent theinner end surface 123 and the both inner side end surfaces 124 and 125 from contacting thesprocket tooth 4 before the frontinner flank surface 164 of theinner link plate 150 starts to engage thesprocket tooth 4 when the chain is in the lateral swinging condition. Here, the entireinner profile surface 122, including the rear innerside end surface 125, is located radially outwardly from the engagement starting point P5 before the frontinner flank surface 144 starts to engage thesprocket tooth 4, and the no part of theguide plate 110 overlaps thesprocket tooth 4. - The
guide plate 110 is configured to avoid contact between theinner profile surface 122 of theguide plate 110 and thesprocket tooth 4 b, or so that theguide plate 110 does not overlap thesprocket tooth 4 when seen from the side, throughout the interval from the start of the engagement of the frontinner flank surface 144 of theinner link plate 150 with thesprocket tooth 4 until the bothouter flanks intermediate link plate 130 located ahead of theinner link plate 150 seat on thesprocket 3 by contact respectively withsprocket tooth 4 c ahead of thesprocket tooth 4 a andsprocket tooth 4 b. - Accordingly, the rear inner
side end surface 125 of the guide plate is configured so that it is prevented from contacting thesprocket tooth 4 or so that the rear innerside end surface 125 does not overlap thesprocket tooth 4 when seen from the side, throughout the interval from the start of engagement of theinner link plate 150 with thesprocket tooth 4 until theintermediate link plate 130 located ahead of theinner link plate 150 seats on thesprocket 3. - The positions of the engagement starting points P3 and P5 described above and the configuration of the
guide plate 110 with respect to thesprocket tooth 4 described above prevent theguide plate 110 from contacting thesprocket tooth 4 before the intermediate andinner link plates silent chain 100 is operated while in the lateral swing condition. - With the configuration described above it is possible, even when the chain is in a laterally swinging condition, to maintain normal engagement wherein the
link plates silent chain 100 first contact thesprocket tooth 4 in the same manner in which they contact the sprocket tooth when the silent chain is traveling in its normal position. Because it is possible to prevent the frictional loss and noise otherwise caused by the contact of theguide plate 110 and thesprocket tooth 4, improve power transmitting efficiency and noise performance can be realized. - Because the
inner profile surface 122 is located radially outward relative to the engagement starting points P3 and P5, it is possible to downsize theguide plate 110 in the radial direction and to reduce the weight of the guide plate. Furthermore, because theguide plate 110 is configured to prevent the rear innerside end surface 125 of theguide plate 110 from contacting thesprocket tooth 4 from the start of engagement of theinner link plate 150 with the sprocket until theintermediate link plate 130 seats on the sprocket, it is possible to downsize theguide plate 110 still further by reducing its radial dimensions. - Because the tensile hardness of the
guide plate 110 is smaller than the bending rigidity of the connectingpins 105 it is possible to suppress warping of the guide plates due to bending of the connecting pins. Suppression of bending of the guide plates, in turn reduces the frictional loss caused by excessive frictional contact between the guide plates and adjacent outermost intermediate link plates. - A further reduction of frictional loss is realized by configuring the
back surfaces 121 of the guide plates so that they are prevented from contacting the sliding contact surface of a chain guide on which the backs of the intermediate and inner link plates slide. - The concave configuration of the back surface of the
guide plate 110 also reduces the tensile hardness of the guide plate, reducing the tendency of the connecting pins to bend and cause warping of the guide plate as a result of tension on the chain - The convex, arc-shaped configurations of the
backs backs - In a modification shown in
FIG. 7 , aninner link plate 150 can be a sliding-contact link plate theback surface 161 of which has an arcuate shape in the direction of chain travel and an arc-shaped transverse section in the direction of the width of the chain. Theintermediate link plates 130 in the guide rows, and, optionally, some of the otherinner link plates 150 in the non-guide rows, can be configured to avoid contact with the sliding contact surface of a guide. - Alternatively, as shown in
FIG. 8 , anintermediate link plate 130 of the guide rows, can a sliding-contact link plate theback surface 141 of which has an arcuate shape in the direction of chain travel and an arc-shaped transverse section in the direction of the width of the chain. Theinner link plates 150, and optionally one or more of the otherintermediate link plates 130 can be configured to avoid the contact with the sliding contact surface of a guide. - With the arrangements shown in
FIGS. 7 and 8 , the use of non-sliding-contact link plates makes it possible to reduce the contact area between the chain and the sliding contact surface of a chain guide with a resulting reduction in frictional loss. - Although the invention is described with reference to a driving sprocket wherein contact between a sprocket tooth and a guide plate before the start of engagement with a link plate tooth is avoided, advantages of the invention can be realized by configuring the chain so that a similar effect is realized at the engagement of the chain with a driven sprocket. Here, if the sprocket is a driven sprocket, the engagement starting points P3 and P5 are located on the rear
inner flanks - The silent chain may be of a type other than the inner-flank-engaging and outer-flank-seating type chain, such as an outer-flank-engaging and outer-flank-seating type chain or an inner-flank-engaging and inner-flank-seating type chain.
- Advantages of the invention can be realized both in an endless silent chain, or in a reciprocating silent chain not formed into an endless loop.
Claims (5)
Applications Claiming Priority (2)
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JP2011193205A JP5634357B2 (en) | 2011-09-05 | 2011-09-05 | Silent chain |
JP2011-193205 | 2011-09-05 |
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US8974335B2 US8974335B2 (en) | 2015-03-10 |
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JP (1) | JP5634357B2 (en) |
KR (1) | KR101473056B1 (en) |
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DE (1) | DE102012215204B4 (en) |
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US20120157252A1 (en) * | 2009-08-31 | 2012-06-21 | Borgwarner Inc. | Silent chain |
US20120196712A1 (en) * | 2011-02-01 | 2012-08-02 | Tsubakimoto Chain Co. | Silent chain transmission system |
US20130203538A1 (en) * | 2012-02-03 | 2013-08-08 | Tsubakimoto Chain Co. | Chain |
US10400869B2 (en) * | 2016-09-02 | 2019-09-03 | Tsubakimoto Chain Co. | Chain drive mechanism |
US20210324941A1 (en) * | 2017-08-08 | 2021-10-21 | Shimano Inc. | Bicycle chain |
US20220003295A1 (en) * | 2019-03-22 | 2022-01-06 | Daido Kogyo Co., Ltd. | Chain transmission device |
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CN103375552A (en) * | 2012-04-26 | 2013-10-30 | 株式会社椿本链条 | Silent chain transmission device |
JP5421448B1 (en) * | 2012-11-22 | 2014-02-19 | 大同工業株式会社 | Silent chain and silent chain transmission |
DE102015008662A1 (en) * | 2015-07-03 | 2017-01-05 | Sram Deutschland Gmbh | Single sprocket for a bicycle forward crank assembly |
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-
2012
- 2012-08-28 US US13/596,157 patent/US8974335B2/en active Active
- 2012-08-28 DE DE102012215204.0A patent/DE102012215204B4/en active Active
- 2012-08-29 KR KR1020120095181A patent/KR101473056B1/en active IP Right Grant
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US20120157252A1 (en) * | 2009-08-31 | 2012-06-21 | Borgwarner Inc. | Silent chain |
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Also Published As
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JP2013053702A (en) | 2013-03-21 |
CN102979853B (en) | 2015-03-25 |
KR101473056B1 (en) | 2014-12-15 |
KR20130026388A (en) | 2013-03-13 |
GB201215604D0 (en) | 2012-10-17 |
US8974335B2 (en) | 2015-03-10 |
JP5634357B2 (en) | 2014-12-03 |
DE102012215204B4 (en) | 2018-08-16 |
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GB2494301A (en) | 2013-03-06 |
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